.aside {
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 200px;
    height: 100%;
    background-color: #9f9f9b;
}

.aside a {
    width: 100%;
    display: flex;
    justify-content: center;
    text-decoration: none;
    font-size: 20px;
    color: #000;
    padding: 10px 0;
}
.aside a.active{
    background-color: cadetblue;
}